Oil Pressure fluctuation

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MadCat52
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Just about to replace my sender unit (second in 5 years and about 20k miles). Really want to keep original Caterham dial as part of a matching set, which I understand can't be done with mechanical gauge, so interested in remote mounting. Does it last longer when mounted remotely?

Bob

Jonathan Kay
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There are several suggestions that they do, and it seems plausible.

But I don't think that I've seen any convincing data.

Jonathan

John Vine
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Does it last longer when mounted remotely?

You could try asking CC themselves, as they offered the remote-mounting kit for exactly that reason.  

JV

bjw
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Perhaps vibration can cause the sender to fail, but that's certainly not always the problem.

Recently my (2016) sender started to behave erratically in the traditional manner. Testing off the car with a compressor and a multimeter showed a pattern of resistance variations which suggested that the mechanics were moving correctly but the wiper of the variable resistor was making poor contact.  Either the contact pressure was low, or there was contamination on the working surface of the resistance wire.

In the hope it was just contamination I drilled a couple of 2.5mm holes on opposite sides of the case and liberally blasted contact cleaner through each one. Cycling the pressure up and down quickly between 0 and 7Bar* a few times (sweeping the wiper from one end to the other) sorted out the resistance issues completely. Covered the holes with some aluminium tape and refitted. Normal operation was restored.

Since the chamber is sealed at manufacture it's not clear how the contact surfaces become contaminated. I don't know if there's a rubber seal at the rolled over seam, but there seems to be one at the terminal. Speculation: Perhaps the seal isn't good enough, or there's moisture present when the unit is closed which leads to corrosion in the long term, or maybe the rubber or some other sealing compound is outgassing. (If it is some sort of outgassing then the lower operating temperature of a remotely mounted sensor may reduce it..?)

I wouldn't like to predict how long the treatment will last, but to repeat it won't take long and contact cleaner is cheap...

As a matter of interest has anyone ever actually cut open a bad unit and found evidence of mechanical damage?

Cheers,

Barry


* (Note the sender is only rated for 7bar even though the gauge goes to 8...)

tweeky
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they offered the remote-mounting kit for exactly that reason

I've got a unsed remote sender kit at home !! for sale if any body wants it.

Jonathan Kay
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Yes, please.

Jonathan

tweeky
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Johathan,

 

working nights at the moment so i`ll try to get photo of the kit in the next couple of days. Be warned there's no instructions that's how it arrived from Caterham.

Jonathan Kay
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Thanks.

No rush.

Jonathan

tweeky
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Jonathan,

You have a message 

paul richards
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Yes. Dissected a sender and it was a mess from ingress of water. It seems to get in around the electrical spade connector. I sealed this on the replacement and mounted remotely out of the direct weather (behind the radiator) and it lasted quite some time (6+ years) and was still going strong. I decided to replace with mechanical gauge as I preferred the less damped action and also the wider sweep of the needle giving a more accurate reading. 

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